I've been working on a small stack language for the BEAM in my free time called 'Xlerb'.
I read Starting Forth and thought it would be interesting to see if you could send messages to other stacks etc, and the BEAM seemed like a great fit.
Xlerb is a small leex/yecc grammar and a simple-ish compiler that takes Forth-ish code and turns it into regular BEAM modules.
The modules it produces just export functions from stack to stack, so there's a good interop story with Elixir/Erlang (if you'd ever want to do that?).
I've the syntax a bit beyond a 'strict' forth with pattern matching, that makes it feel a bit more natural of a BEAM language (with different function heads etc). It was a fun exercise translating that into the Erlang primitives of case, send, receive etc.
I've got a website at https://xlerb.wtf with a bit more, and you can get the code/compiler/repl at https://github.com/shawa/xlerb
Let me know what you think!